Calcium hypochlorite compositions

ABSTRACT

Stable compositions of calcium hypochlorite containing selected hydrated inorganic salts having a sufficiently high enthalpy and the ability to provide water release to sufficiently quench reactions and reduce the potential for conflagration.

FIELD OF THE INVENTION

The present invention relates generally to stable compositions ofcalcium hypochlorite, and more particularly compositions that haveimproved stability. In a further aspect, the present invention relatesto a method of stabilizing calcium hypochlorite.

BACKGROUND OF THE INVENTION

Calcium hypochlorite (cal hypo) has been around for nearly 100 years.Initially, unrefined cal hypo, which was known as “bleaching powder”,was produced containing about 35% available chlorine. In the 1930's,manufacturers succeeded in refining cal hypo; anhydrous cal hypo wasproduced containing 80% available chlorine or higher. After severalfires, research was done that showed that cal hypo at 70% availablechlorine was less vigorous than 80% available chlorine; therefore,manufacturers limited anhydrous cal hypo to 70% available chlorine.

Anhydrous calcium hypochlorite containing 70% available chlorine wasinvolved in many shipboard fires that occurred during the late 1960'sand early 1970's and caused major property damage and loss of life. Dueto these incidences, the manufacturers of cal hypo produced lessreactive hydrated forms of cal hypo. See, U.S. Pat. Nos. 3,544,267;3,895,099 and 4,053,429. They also patented hydrated salts mixed withanhydrous cal hypo to form hydrated cal hypo. See, U.S. Pat. No.3,793,216.

Hydrated calcium hypochlorite containing at least 65% available chlorineand from about 5.5 to 16% water are available as shown in ChemicalEconomics Handbook, Hypochlorite Bleaches (2003) SRI International.Those containing 5.5 to 10% moisture became the most widely availablecommercial form and designated by the United Nations as UN 2880. Even at10% moisture, dihydrate cal hypo is not completely saturated with water;complete saturation would be approximately 17% water. Commercial calhypo is lower in water than saturation because higher water contentwould have an adverse effect on the stability of cal hypo. The loss ofstability of the available chlorine in cal hypo due to the presence ofmoisture content, temperature and humidity is well known in the art;see, U.S. Pat. Nos. 3,544,267, 4,355,014 and 4,965,016, and Bibby andMilestone, J. Chem. Tech. Biotechnol (34A), pp. 423-430 (1984).

The commercialization of hydrated cal hypo in addition to changes instorage of the material aboard ships proposed by Clancey, Journal ofHazardous Materials, (1) pp. 83-94, (1975/76) made cal hypo safer inmarine transport. This was seemingly confirmed by the work of Mandell,Fire Technology (7), pp. 157-161 (1971), that showed an endotherm forhydrated cal hypo at 40° C. according to Differential ScanningCalorimetry (DSC). This endotherm, which is not present in the anhydrousmaterial, is thought to provide a heatsink to quench an exotherm so thatno propagation occurs. This investigation also used tests incorporatinglit matches, lit cigarettes, or one drop of glycerin as an ignitionsource for the calcium hypochlorite.

A study by Cardillo, Rev. Combust, (48) pp, 300-305 (1994), concludedthat the addition of moisture lowers the temperature at which exothermicdecomposition of cat hypo takes place. They also concluded that the heatgenerated during the decomposition would be increased. Gray andHalliburton, Fire Safety Journal (35), pp. 223-239 (2000), investigatedhydrated cat hypo based on marine fires that happened in the late1990's. They concluded that hydrated cal hypo had a lower criticalambient temperature for large quantities of material than was previouslythought. Both studies confirm that hydrated cal hypo is not as stable toexothermic decomposition than was previously reported. The UN Transportof Dangerous Goods (TDG) subcommittee confirmed this using aself-accelerating decomposition test (SADT) on various manufactured calhypos. See, UN/SCETDG/21/INF.8 (2002).

While improving the available chlorine and reducing reactivity of calhypo has been going on for a long time, another difficulty using calhypo, namely, the formation of calcium scale, has been equallyinvestigated. Since the earliest use of cal hypo as a liquid bleachingcompound, scale, such as calcium carbonate, has been an issue. Scaleinhibitors such as sodium pyrophosphate, sodium tripolyphosphate, sodiumpolyacrylate, phosphonobutane tricarboxylic acid and alkali salts ofPESA and/or polymaleic acid have been added to improve the clarity ofcal hypo solutions or prevent the deposition of calcium sensitive soapsand detergents or reduce scaling in equipment feeding cal hypo. Mullins,in U.S. Pat. No. 5,112,521 and Faust, U.S. Pat. No. 3,669,894, alsoconfirm what is known to those skilled in the art; it is difficult tofind additives that can be admixed with cal hypo since those additivescan affect stability of the cal hypo causing a loss of availablechlorine especially at elevated temperatures.

Investigators have added materials that reduced dusting and increasedthe resistance to ignition by lit cigarettes, matches, or a drop ofglycerin using spray-grained low melting hydrated inorganic salts suchas: magnesium sulfate hydrates, sodium tetraborate hydrates, aluminumsulfate hydrates, and sodium phosphate hydrates; see, U.S. Pat. No.4,146,676. Additionally, coatings of alkaline metal salts like sodiumchloride and alkaline materials like calcium hydroxide may also be usedto buffer compositions above pH 9. Both '676 and Pickens, WO 99/61376,agree that the presence of acidic material causes a decrease in storagestability.

Other investigators have added materials to calcium hypochlorite toprovide other functions. For water treatment, Loehr, U.S. Pat. No.4,747,978, added 0.1 to about 3% water soluble aluminum salts toincrease water clarity. Pickens added hydrated aluminum salts as long asthey were neutralized with an equivalent amount of hydrated borate salt.Girvan, U.S. Pat. No. 5,676,844, added hydrated borate salts or boricacid to improve the properties of cal hypo. Robson in U.S. Pat. No.3,560,396 used spray-dried sodium nitrate preparations of cal hypo toreduce reactivity.

Only two inventive compositions containing admixed formulations withcalcium hypochlorite disclose increased stability to loss of availablechlorine. Jaszka, U.S. Pat. No. 3,036,013, adds a solution of a solublesalt that would react with the calcium hypochlorite to form an insolublecalcium salt at the surface of each granule. This coating would increasethe stability of the particle in the presence of humidity and moisture.The coating would also slow the dissolution rate of the composition.Suitable salts include sodium silicate, sodium borate, sodium carbonate,trisodium phosphate, disodium phosphate and potassium fluoride. Thecomposition of Murakami, in U.S. Pat. No. 4,355,014, used at least 5%calcium hydroxide to increase the stability of compositions containingat least 4% and up to 22% moisture. In both cases, the process and/orthe material added result in slowing down the dissolving rate of the calhypo. This is not a desirable effect when adding the material as a drygranular blend in a water treatment application or other applicationsthat needs a quick dose of free available chlorine.

In response to marine fires and retail store fires that occurred duringthe 1990's, cal hypo manufactures and marketers continued to investigatemaking cal hypo safer. Girvan promoted the composition in U.S. Pat. No.5,676,844 as less reactive based on the results of U.S. Pat. No.3,793,216, as well as the algicidal and fungicidal benefits of thecomposition.

U.S. Pat. No. 6,638,446 uses the UN DOT Oxidizer test to classify theirmaterial, which contains magnesium sulfate heptahydrate as anon-oxidizer. This is also the claim by Pickens in WO 99/61376. Thistest, which is used to classify materials as oxidizers, has come underscrutiny due to variability based on relative humidity, cellulosesource, and ignition wire composition and diameter; see, Journal ofLossPrevention in the Process Industries (14), pp. 431-434, (2001) andJournal of Safety and Environment (2), pp. 32-35, (2002). Sincecellulose is hygroscopic, the hydrated water could interfere with theresults of this test. The '446 patent teaches away from other past testsusing a lit cigarette, a lit match, or one drop of glycerin since noneof these tests is demanding due to the absence of fuel. A better test isone that is more severe and also more reproducible than the UN/DOToxidizer test.

Reactivity in compositions shown in U.S. Pat. No. 3,793,216, using onedrop of glycerin were noted by a time delay in reactions as well as thereaction itself and the amount of destruction to the sample. Glycerin aswell as brake fluid are especially reactive with calcium hypochlorite.The reaction with brake fluid has been detailed chemically; see, Journalof Forensic Sciences (36), pp. 902-907, (1991). This exothermic chemicalreaction initially has a delay period until a fireball erupts; thefireball lasts a few seconds and consumes all the brake fluid and muchor all of the calcium hypochlorite depending on the quantity ofmaterials used. The “freshness” of the cal hypo is also a factor in thereaction.

The rationale for changing anhydrous calcium hypochlorite to hydratedcalcium hypochlorite was to make the product safer due to decompositionby a cigarette, spark, or one drop of contamination by an organiccompound. The addition of water to anhydrous cal hypo changed thecharacteristics of the material including a unique hazardous chemicaldesignation of UN 2880; however, hydrated cal hypo is still a highlyreactive material that can be purchased by a consumer. Unsuspectingconsumers are not keenly aware of the potential danger the materialposes. Thus the need exists to make a calcium hypochlorite containingformulation that provides to the consumer a product that is safe totransport, store, and use. Accordingly, there is a need to improve thesafety of calcium hypochlorite formulations to provide a stable, safe,fast dissolving and functional blend for water treatment and otherapplications.

SUMMARY OF THE INVENTION

There is a need for a stable, safer, rapidly dissolving andmultifunctional calcium hypochlorite formulation that can rapidlyprovide free available chlorine to water treatment and otherapplications. The present invention provides a solution for these needs.

BRIEF DESCRIPTION OF DRAWINGS

The present invention will be further understood with reference to theaccompanying drawings, wherein:

FIG. 1 is a chart of temperature over time of 3 Replicate CalciumHypochlorite and Brake Fluid Reaction;

FIG. 2 is a chart of temperature over time for Reactions of CalciumHypochlorite and Brake Fluid (Control) Compared to Calcium HypochloriteBlends and Brake Fluid; and

FIG. 3 is a chart of temperature over time of Calcium Hypochlorite andBrake Fluid Compared to a Blend of Calcium Hypochlorite and SodiumBicarbonate and Brake Fluid.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For the purpose of providing a further understanding of the principlesof the invention, reference will now be made to the preferredembodiments of the present invention. Specific language will be used todescribe the same; nevertheless, it will be understood that nolimitation of the scope of the invention is thereby intended.

Many hydrated salts and other chemicals can produce endothermicreactions upon heating; see WO 99/11455. For hydrated salts, theendothermic reaction generally occurs as part of a phase transition(i.e. solid to liquid) so the endotherm occurs when water is released.Phase transitions occur at different temperatures for various compounds.For simplification purposes, melting point is used herein as the phasetransition point. The phase transition for a given salt may be belowambient temperature (i.e. dipotassium phosphate hexahydrate) or abovethe boiling point of water (i.e. magnesium chloride hexahydrate). See,Thermochemica Acta (67), pp. 167-179 (1983). When this endothermicreaction occurs is critical for the proper release of water for a givenapplication.

The amount of heat energy absorbed varies for various hydratedcompounds. Attributes like percent weight water or the sheer number ofhydrated waters are not good measures of how much heat energy can beabsorbed. Enthalpy, ΔH, is the best means by which to measure the heatenergy absorbed; however, most measurements are made using moles ofmaterial. From a formulation perspective, weight is a more common meansto measure materials thus, the use should be optimized on a weightbasis. For both of these chemical properties, Table 1 was generatedusing various references: CRC Handbook of Chemistry and Physics, 80^(th)Edition (1999), D. R. Lide; CRC Handbook of Chemistry and Physics,52^(nd) Edition (1971), R. Weast; The Merck Index, 13^(th) Edition(2001), M. J. O'Neil, et al.; and Selected Values of ChemicalThermodynamic Properties (1952), F. D. Rossini, et al. Table 1 is anextensive list, but not an exhaustive list. Although pure hydratedinorganic salts and double salts are referenced here, the presentinvention also contemplates other more complex hydrated salts. TABLE 1melting water of Δ Hf molecular Δ H Percent Salt point ° C. hydrationkcal/mol weight cal/gram water aluminum chloride 100 6 −641.1 241.4530.6 44.8 magnesium chloride 117 6 −597.4 203.3 478.2 53.2 lithiumselenide n/a 9 −729.0 255.0 461.6 63.6 sodium carbonate 33-35 10 −975.6286.1 444.9 63.0 lithium chloride n/a 3 −313.5 96.4 439.9 56.1 sodiumhydrogen phosphate 37 12 −1266.4 358.1 433.9 60.4 sodium metasilicate40-48 9 −1002.0 284.2 418.0 57.1 strontium hydroxide 100 8 −801.2 265.8412.0 54.2 trisodium phosphate ˜75 12 −1309.0 380.1 408.8 56.9 potassiumfluoride 19.3 4 −418.0 130.1 402.2 55.4 magnesium sulfate 150 7 −808.7246.5 400.0 51.2 calcium chloride 30 6 −623.2 219.0 394.3 49.4 sodiumsulfate 32.4 10 −1033.5 322.2 386.7 55.9 aluminum sulfate 86 18 −2118.5666.4 385.8 48.7 sodium tetraborate ˜75 10 −1497.2 381.4 371.0 47.3magnesium sulfate 70-80 6 −736.6 228.5 369.0 47.3 magnesium bromide 1656 −575.4 292.2 359.0 37.0 rubidium aluminum sulfate 99 12 −1448.0 520.8356.0 41.5 barium hydroxide 78 8 −799.5 315.5 351.5 45.7 potassiumaluminum sulfate  80-92.5 12 −1447.7 474.4 347.6 45.6 magnesium nitrate89 6 −624.4 256.4 346.5 42.2 sodium hydrogen phosphate 48.1 7 −913.3268.1 340.6 47.1 nickel sulfate 31.5 7 −712.9 280.9 339.3 44.9 zincsulfate 100 7 −735.1 287.5 336.0 43.9 beryllium sulfate ˜100 4 −576.3177.1 333.6 40.7 lithium nitrate 29.9 3 −328.6 123.0 324.6 44.0strontium chloride ˜60 6 −627.1 266.6 308.7 40.6 zinc nitrate 36.4 6−550.9 297.5 299.2 36.3 sodium pyrophosphate 76.3 10 −1468.2 446.1 290.140.4 calcium bromide 38 6 −597.2 308.0 289.3 35.1 copper sulfate 110 5−544.5 249.7 286.2 36.1 copper nitrate 24.4 6 −504.3 295.6 284.5 36.6aluminum nitrate 73 9 −897.3 375.1 275.9 43.2 sodium tetraborate 120 5−1143.5 291.3 263.7 30.9 silver fluoride n/a 4 −331.5 198.9 260.5 36.2calcium iodide n/a 8 −700.7 437.9 252.4 32.9 lithium bromide 44 2 −229.9122.3 250.4 29.5 lithium iodide 73 3 −285.0 187.9 249.2 28.8 strontiumbromide 88 6 −604.4 355.5 243.3 30.4 calcium nitrate ˜40 4 −509.4 236.2229.4 30.5 strontium iodide 90 6 −571.2 449.5 197.8 24.1 sodium bromide36 2 −227.3 138.9 184.4 25.9 strontium nitrate 100 4 −514.5 283.7 176.425.4n/a—not available

For application to calcium hypochlorite, when water is released from asalt hydrate is important. If water is released too easily, the watermay easily transfer to the calcium hypochlorite thus reducing chlorinestability. If water is not released quickly enough, the decomposition ofcal hypo may overwhelm the system during a conflagration. The presentinvention provides blends of at least two hydrated salts with calciumhypochlorite that provide water release to sufficiently quench reactionsand reduce the potential for a conflagration while providing increasedchlorine stability as compared to blends that are currently available.Inventive blends with other endothermic compounds and cal hypo are alsodisclosed herein. Additionally, the blends of the current inventionprovide added benefits to users by incorporating other water treatmentfunctions for various applications of the inventive compositions.

As previously indicated, hydrated calcium hypochlorite is the preferredsanitizer used in the present invention. In the preferred embodiments,hydrated calcium hypochlorite contains at least 55% available chlorine,and more preferably at least 65% available chlorine. Hydrated cal hypoideally contains from 5% to 22% water, and more preferably, the hydratedcalcium hypochlorite contains about 5.5% to 10% water.

The concentration of the hydrated calcium hypochlorite compositions ofthe present invention is between about 40% and 90% by weight.Preferably, the compositions of the present invention contain betweenabout 50% and 85% hydrated calcium hypochlorite. Most preferably, thecompositions of the present invention contain about 60% to 80% hydratedcalcium hypochlorite.

In the preferred embodiment of the invention, the hydrated salt has aphase transition temperature, as defined by melting point, between 19°C. and 200° C., and more preferably between 45° C. and 90° C. The pure,double or complex hydrated salt is an inorganic hydrated salt offluoride, chloride, bromide, iodide, selenide, hydroxide, oxide,phosphate, silicate, borate, carbonate, nitrate and/or sulfate.

The preferred hydrated inorganic salts exhibit an enthalpy expressed incalories/gram of at least 150, more preferably at least 250calories/gram.

Inorganic salt hydrates that meet these enthalpy and melting pointcriteria are the hydrates of aluminum chloride, magnesium chloride,lithium selenide, sodium carbonate, lithium chloride, sodium hydrogenphosphate, sodium metasilicate, strontium hydroxide, trisodiumphosphate, potassium fluoride, magnesium sulfate, calcium chloride,sodium sulfate, aluminum sulfate, sodium tetraborate, magnesium sulfate,magnesium bromide, rubidium aluminum sulfate, barium hydroxide,potassium aluminum sulfate, magnesium nitrate, sodium hydrogenphosphate, nickel sulfate, zinc sulfate, beryllium sulfate, lithiumnitrate, strontium chloride, zinc nitrate, sodium pyrophosphate, calciumbromide, copper sulfate, copper nitrate, aluminum nitrate, sodiumtetraborate, silver fluoride, calcium iodide, lithium bromide, lithiumiodide, strontium bromide, calcium nitrate, strontium iodide, sodiumbromide, and strontium nitrate. Representative hydrates are shown in theabove Table 1.

Preferred compositions of the present invention include a composition ofreduced potential for conflagration comprising hydrated calciumhypochlorite and at least two members selected from the group consistingof magnesium sulfate heptahydrate, potassium aluminum sulfatedodecahydrate, trisodium phosphate dodecahydrate, sodiumtripolyphosphate hexahydrate and sodium tetraborate decahydrate.

More particularly a preferred composition of the present invention is acomposition of reduced potential for conflagration comprising hydratedcalcium hypochlorite, sodium tripolyphosphate hexahydrate, magnesiumsulfate heptahydrate, potassium aluminum sulfate dodecahydrate andtrisodium phosphate dodecahydrate.

Still more particularly a more preferred composition of the presentinvention is a composition which comprises about 40 to about 90%hydrated calcium hypochlorite, 0.1 to 19% magnesium sulfateheptahydrate, 0.1 to 19% potassium aluminum sulfate dodecahydrate, 0.1to 19% trisodium phosphate dodecahydrate and 0.1 to 10% sodiumtripolyphosphate hexahydrate.

According to another aspect of the invention, there are providedadditive compositions for imparting reduced tendency for conflagrationof a calcium hypochlorite blended with sodium tripolyphosphatehexahydrate, comprising at least one member selected from the groupconsisting of magnesium sulfate heptahydrate, potassium aluminum sulfatedodecahydrate, trisodium phosphate dodecahydrate and sodium tetraboratedecahydrate.

In a still further aspect of the present invention, there is provided amethod wherein there is added to the calcium hypochlorite a blend whichcomprises 40 to about 90% hydrated calcium hypochlorite, 0.1 to 19%magnesium sulfate heptahydrate, 0.1 to 19% potassium aluminum sulfatedodecahydrate, 0.1 to 19% trisodium phosphate dodecahydrate 0.1 to 10%sodium tripolyphosphate hexahydrate, and 0.1-10% sodium tetraboratedecahydrate and 0.1-10% sodium tetraborate decahydrate.

The sanitizing compositions of the present invention are preferablysolid granulated products of any size or shape above 150 microns indiameter. Granular cal hypo sanitizing compositions are preferred overpowder cal hypo sanitizing compositions because of inhalation hazardsinherent to powders (respirable powders are particles or particleagglomerates less than about 10 microns in diameter). The granularsanitizing compositions of the present invention are prepared by anyknown static or in-process mixing or blending technology such as aV-blender, ribbon blender, screw feeders, and the like. Alternatively,dry particle-size enlargement methods, preferably co-compaction orgranulation may be used to compact inventive mixtures from powder blendsinto granules.

Additional components such as scale inhibitors, water clarifiers,anti-caking agents, humectants, binders, bulking agents, mold releaseagents, corrosion inhibitors, surfactants, glidants, or dyes may beincorporated into compositions of the present invention. The selectionof such components is within the capability of those skilled in the art.

Compositions of the present invention are preferably used to treatrecirculating water systems like swimming pools, spas, hot tubs, toiletbowls, reflecting pools, industrial water systems, fountains, etc. Thepresent invention will sanitize, clarify, and reduce algae occurrence inwater systems by contacting an effective amount of the sanitizingcomposition of the present invention with the water system through anappropriate application method. The methods of application may be manualor automatic.

Reference will now be made to specific examples. It is to be understoodthat the examples are provided to more completely describe preferredembodiments, and no limitation to the scope of the invention is intendedthereby.

EXAMPLE 1

FIG. 1 shows the predictability of a single batch of calciumhypochlorite reacting with brake fluid. As described earlier, calciumhypochlorite reacts violently with Dot 3 brake fluid (Prestone) in afree radical depolymerization reaction of polyethylene glycol ether. Thereaction of 50 grams of calcium hypochlorite and 10 milliliters (mls) ofbrake fluid is predictable for a given batch of calcium hypochlorite.Variations may occur with the reaction from different batches of calhypo based on the attributes of the batch of calcium hypochlorite, suchas age, moisture content and particle size.

The temperature measurement made in FIG. 1 was made with an IRthermometer with data acquisition software (Fisher Scientific). Thetemperature maximum of the thermometer is 300 degrees Celsius (C.). Thismaximum temperature is exceeded for the time period when the curve isflat at 300° C.

FIG. 2 shows the reaction of mixtures of various hydrated compoundsblended with calcium hypochlorite. The blends contain 15 grams of thehydrated material and 35 grams of calcium hypochlorite. These arecompared to a control containing 50 grams of calcium hypochlorite. Theenthalpy (ΔH) and melting point (mp) are attributes of each compoundthat change the reaction curve. Potential interactions by each compoundwith calcium hypochlorite may also cause changes to the reaction curveas well as product stability.

FIG. 2 clearly shows that a low melting point is clearly the mostimportant factor in reducing the reaction as shown by the reducedtemperature output of sodium sulfate decahydrate (mp 32.4° C.) andsodium metasilicate nonahydrate (mp 40° C.). It is also clear that theenthalpy is also critical since the reaction with sodium sulfatedecahydrate is substantially reduced (ΔH=386.7 calories/gram); however,the reaction with sodium metasilicate nonahydrate (ΔH=418.0calories/gram) provides nearly total quenching of the reaction.

EXAMPLE 2

Reducing the reactivity of calcium hypochlorite is only one aspect ofthe current invention. Few additives are even compatible with cal hypo.The inventive mixtures herein are also stable providing high availablechlorine even after being subjected to conditions that have a degradingeffect on the available chlorine present in calcium hypochlorite. Otheraspects of the invention will also be made known.

As described earlier, cal hypo degrades over time. This is acceleratedby the presence of heat and moisture. Inventive mixtures were stored at40 degrees C. under ambient humidity conditions in a convection oven.These conditions would be indicative of potential warehouse andtransport conditions for the material. Table 2 shows the increasedchlorine stability of the inventive formulations.

Each 200 gram sample contained 70% (47% available chlorine) calciumhypochlorite, 2% Sodium tripolyphosphate hexahydrate, and the balance ofthe composition as shown below. The formulation components are magnesiumsulfate heptahydrate (MgSO₄-7H₂O), trisodium phosphate dodecahydrate(TSP.12 H₂O), sodium tetraborate decahydrate (Borax.10 H₂O), andpotassium aluminum sulfate dodecahydrate (K-Alum.12H₂O). TABLE 2 MgSO4TSP Borax K-Alum Days in Storage Material Percent Available 7H2O 12H2010H20 12H2O Storage Temp ° C. Consistency Chlorine 28.0% — — — 56 40 Dry28.3 — 28.0% — — 61 40 Dry 28.3 — — 28.0% — 63 40 Dry 22.3 — — — 28.0%60 40 Moist 30.7 7.0% 7.0% 7.0% 7.0% 62 40 Dry 38.2 9.3% 9.3% — 9.3% 6140 Dry 42.7 9.3% 18.7% — — 56 40 Dry 35.5 — 9.3% — 18.7% 55 40 Dry 38.1— 18.7% — 9.3% 59 40 Dry 33.7 9.3% — 9.3% 9.3% 55 40 Dry 32.5 3.5% 17.5%3.5% 3.5% 61 40 Dry 37.9 3.5% 3.5% 3.5% 17.5% 60 40 Moist 37.4 3.5% 3.5%17.5% 3.5% 54 40 Dry 18.8

The experiment above showed that trisodium phosphate dodecahydrateseemed to have a positive effect on chlorine stability and sodiumtetraborate decahydrate seemed to have a negative effect on stability athigher levels. Potassium aluminum sulfate dodecahydrate in high amountsdid not have a negative effect on chlorine stability but did make thesamples moist which is not acceptable for a commercial product.

EXAMPLE 3

Based on the results of Example 2, a simplified experiment on materialconsistency and product flowability was performed. Sodium tetraboratedecahydrate was removed from the experiment. The 200 gram samples werecomposed of a fixed amount of potassium aluminum sulfate at a nominalconcentration of 9% to provide benefits to the pool water whileminimizing the effect on product flowability. The formulation contained2% sodium tripolyphosphate hexahydrate and 70% calcium hypochlorite.Magnesium sulfate heptahydrate and trisodium phosphate dodecahydratewere formulated in different percentages to make up the final 19% of theformula. A control containing straight calcium hypochlorite was used asa base for comparison of flowability results. Samples were stored in aconvection oven at 50° C. for 6 days under ambient humidity conditions.This temperature is indicative of possible short-term transport andstorage conditions that a product may be exposed to. The results areshown in Table 3. TABLE 3 MgSO4 TSP Days in Storage Flowability MaterialFlowability 7H2O 12H2O Storage Temp ° C. Grade Consistency DescriptionControl 6 50 10 Dry Free flowing granules 19.0% — 6 50 9 Slightly moistSlight granule caking — 19.0% 6 50 2 Dry Dry caked granules 14.3% 4.7% 650 10 Dry Free flowing granules 4.7% 14.3% 6 50 6 Dry Free flowing aftertapping container 9.5% 9.5% 6 50 6 Dry Free flowing after tappingcontainer

The calcium hypochlorite control material was a free-flowing granularmaterial after exposure to the test conditions. The only sample that wasequal to cal hypo in material consistency and flowability was the samplecontaining 14.3% magnesium sulfate heptahydrate and 4.7% trisodiumphosphate dodecahydrate. The samples containing 19% magnesium sulfateheptahydrate were slightly moist with granules adhering to each otherand the container sides. The samples containing 19% trisodium phosphatedodecahydrate were dry and caked with significant effort needed to breakgranular masses. The samples containing 4.7% and 14.3%, and 9.5% of eachmagnesium sulfate heptahydrate and trisodium phosphate dodecahydrate,respectively, were free flowing after tapping the sample container.

EXAMPLE 4

Various 800 gram samples of different formulations were weighed, blendedand packaged in high density polyethylene (HDPE) commercial packaging.These larger scale mixtures in commercial packaging were made to teststability, material consistency and flowability as well as pH. Themixtures began with 70% (47% available chlorine) calcium hypochloritehydrated, 2% sodium tripolyphosphate hexahydrate, and the balance of 28%contained mixtures of magnesium sulfate heptahydrate, trisodiumphosphate dodecahydrate, and potassium aluminum sulfate dodecahydrate.These samples were stored at 40° C. in a convection oven and ambienthumidity conditions for a period of more than 3 months. The results areshown in Table 4. TABLE 4 MgSO4 TSP K-Alum Days in Storage MaterialPercent Available 7H2O 12H2O 12H2O Storage Temp ° C. ConsistencyChlorine pH 28.0% — — 110 40 Slightly Moist 27.3 10.1 — 28.0% — 110 40Slightly Moist 19.2 11.1 — — 28.0% 110 40 Very Moist 27.5 8.1 14.0%14.0% — 110 40 Dry 34.8 10.4 — 14.0% 14.0% 110 40 Dry 36.1 9.1 14.0% —14.0% 110 40 Moist 20.0 8.3 9.3% 9.3% 9.3% 110 40 Dry 34.5 9.0

The results of Example 4 definitively show a synergistic effect thattrisodium phosphate dodecahydrate has on the stability and materialconsistency of cal hypo formulas that contain either magnesium sulfateheptahydrate or potassium aluminum sulfate or both materials. Thesestable formulas also have a pH as low as 9.0. As stated earlier by thoseskilled in the art, acidic materials added to calcium hypochlorite makecal hypo unstable. A pH closer to neutral is an advantage in many watertreatment applications especially swimming pools and spas since chlorineefficacy and swimmer comfort is optimized at pH 7.5.

EXAMPLE 5

Although inorganic salt hydrates release water to quench the reaction ofcal hypo and brake fluid other inorganic compounds can also have aneffect on this reaction. Boric acid decomposes when heated and releaseswater thus effectively reducing an exothermic reaction. A mixture of 30%sodium bicarbonate and 70% calcium hypochlorite decomposes when heatedto release carbon dioxide thus reducing an exothermic reaction. This isillustrated in FIG. 3.

Based on the results of Examples 1-4, a range for the various inorganicsalt hydrates can be specified. Stable formulations containing up to 30%each of 2 salt hydrates. The salt hydrates can be selected from thegroup consisting of magnesium sulfate heptahydrate, potassium aluminumsulfate dodecahydrate, trisodium phosphate dodecahydrate, sodiumtripolyphosphate hexahydrate and sodium tetraborate decahydrate. Morepreferably compositions could contain from 0.1 to 19% magnesium sulfateheptahydrate, 0.1 to 19% potassium aluminum sulfate dodecahydrate, 0.1to 19% trisodium phosphate dodecahydrate, 0.1 to 10% sodiumtripolyphosphate hexahydrate, and 0.1 to 10% sodium tetraboratedecahydrate.

Further variations and modifications of the foregoing will be apparentto those skilled in the art and are intended to be encompassed by theclaims appended hereto.

1. A composition comprising a mixture of hydrated calcium hypochloritewith at least two hydrated inorganic salts, having an enthalpy, ΔH, ofat least 150 calories/gram, and having a phase transition temperature,as defined by the melting point of 19° C. to 200° C., whereby saidmixture provides water release in an endothermic reaction tosufficiently quench dangerous reactions and reduce potential for aconflagration while providing increased chlorine stability as comparedto blends containing a single hydrated inorganic salt.
 2. Thecomposition according to claim 1, the hydrated calcium hypochloritecontains at least 55% available chlorine.
 3. The composition accordingto claim 2, wherein the hydrated calcium hypochlorite contains at least65% available chlorine.
 4. The composition according to claim 1, whereinthe hydrated calcium hypochlorite contains from 5% to 22% water.
 5. Thecomposition according to claim 3, wherein the hydrated calciumhypochlorite contains at least 5% to 22% water.
 6. The compositionaccording to claim 5, wherein the hydrated calcium hypochlorite containsabout 5.5% to 10% water.
 7. The composition according to claim 1,wherein the hydrated calcium hypochlorite is present in the amount of40% to 90% by weight.
 8. The composition according to claim 7, whereinthe concentration of the hydrated calcium hypochlorite is about 50% to85% by weight.
 9. The composition according to claim 8, wherein theconcentration of the hydrated calcium hypochlorite is about 60% to 80%by weight.
 10. The composition according to claim 1, wherein thehydrated inorganic salt has a phase transition temperature as defined bythe melting point of 19° C. to 200° C.
 11. The composition according toclaim 10, wherein the hydrated inorganic salt has a phase transitiontemperature as measured by the melting point between about 45° C. and90° C.
 12. The composition according to claim 1, wherein the hydratedinorganic salt is an inorganic hydrated salt of fluoride, chloride,bromide, iodide, selenide, hydroxide, oxide, phosphate, silicate,borate, carbonate, nitrate, or sulfate.
 13. The composition according toclaim 12, wherein the hydrated inorganic salt is a hydrated memberselected from the group consisting of aluminum chloride, magnesiumchloride, lithium selenide, sodium carbonate, lithium chloride, sodiumhydrogen phosphate, sodium metasilicate, strontium hydroxide, trisodiumphosphate, potassium fluoride, magnesium sulfate, calcium chloride,sodium sulfate, aluminum sulfate, sodium tetraborate, magnesium sulfate,magnesium bromide, rubidium aluminum sulfate, barium hydroxide,potassium aluminum sulfate, magnesium nitrate, sodium hydrogenphosphate, nickel sulfate, zinc sulfate, beryllium sulfate, lithiumnitrate, strontium chloride, zinc nitrate, sodium pyrophosphate, calciumbromide, copper sulfate, copper nitrate, aluminum nitrate, sodiumtetraborate, silver fluoride, calcium iodide, lithium bromide, lithiumiodide, strontium bromide, calcium nitrate, strontium iodide, sodiumbromide and strontium nitrate.
 14. The composition according to claim 1,wherein the hydrated inorganic salt is a pure hydrated inorganic salt ora double or other complex hydrated salt.
 15. A composition of reducedpotential for conflagration comprising hydrated calcium hypochlorite andat least two members selected from the group consisting of magnesiumsulfate heptahydrate, potassium aluminum sulfate dodecahydrate,trisodium phosphate dodecahydrate, sodium tripolyphosphate hexahydrateand sodium tetraborate decahydrate. 16-31. (canceled)